Checks to see if an index exists on a table for a given index definition

Examples

# Check an index existsindex_exists?(:suppliers,:company_id)# Check an index on multiple columns existsindex_exists?(:suppliers,[:company_id,:company_type])# Check a unique index existsindex_exists?(:suppliers,:company_id,:unique=>true)# Check an index with a custom name existsindex_exists?(:suppliers,:company_id,:name=>"idx_company_id"